1. Field of the Invention
This invention relates to devices and methods for converting between a logical block address (LBA) expressed in hexadecimal (Hex) format and a minute second frame (MSF) location expressed in binary coded decimal (BCD) format on a data carrier, such as a compact disk read only memory (CD-ROM).
2. Description of the Related Art
When designing decoder circuits to decode information stored on data carriers such as CD-ROMs, it is often necessary to design or to use predefined logic to convert between a logical block address (LBA) expressed in hexadecimal (numbering system having a radix of 16, hereafter "Hex") format and a minute second frame (MSF) location expressed in binary coded decimal (more specifically, the 8421 BCD code, hereafter "BCD") format. Indeed, the location of information stored on CD-ROMs is expressed in MSF format, while the decoder and the host most often express addresses as LBA, which are expressed in Hex format. Such logic may be incorporated as a functional block in electronic design automation (EDA) software, which is a generic term for a class of software tools that help engineers develop integrated circuits (ICs). Such tools convert a high level descriptive language, such as VERILOG.RTM. or VHDL (IEEE 1076 standard) into a logical gate representation that may be implemented in silicon. To translate the high level descriptive language into a logical gate representation typically requires a compile operation. Providers of such EDA software, such as Synopsis, Inc. of Mountain View, Calif. sell licenses to companies wishing to use their software. The number of compile operations that may be carried out simultaneously is limited to the number of licenses that are purchased. If all of the licenses that have been purchased are currently in use, integrated circuit designers wishing to invoke the functional block that converts between LBA and MSF address locations are prevented from doing so, thereby decreasing their productivity. In turn, this may increase the time to market and/or cost of the resultant IC design.
It is, therefore, desirable to provide methods and devices to convert between LBA and MSF address formats of a data carrier such as a CD-ROM without invoking the functional block(s) of the EDA software predefined for that purpose. It is also desirable to provide methods and devices to quickly and efficiently convert between LBA and MSF address formats without resorting to the traditional methods carried out by such predefined functional block, which convert between codes by dividing and multiplying by 16. Such methods and devices, moreover, should yield a lower resultant gate count than the aforementioned predefined functional blocks, at least for 8 bit applications.